Valve-gear



3 Sheets-Sheet 1.

(No Model.)

P. PISTOR.

VALVE GEAR.

No. 550,725. Patented Dec. 5, 1895.

INVEN'TDR .22

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AN DREW BVGHANAM. PNOTO-UYHO.WASHI NGTUNJIC (No Model.) 3 Sheets-Sheet 2.

' P. PISTOR.

VALVE GEAR. I

No. 550,725. n g Dec. 3, 1895.

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P. PISTOR. VALVE GEAR.

liatented Deb. 3; 189 5.

Dam 27: Par d J WITNESS S:' INVENTOR MWMW ANDREW EGFNMM. PHGTO'UTNQWASNINGTDN. 0-D

' tions between the governor, the valve-oper- Corliss-engine valve'gear; and the object of UNTTED STATES PATENT OFFICE.

PHILIP PISTOR, OF PHILADELPHIA, PENNSYLVANIA.

VALVE- GEAR.

SPECIFICATION forming part of Letters Patent No. 550,725, dated December 3, 18 95.

Application filed December 26,1893.

To all whom it may concern:

Be it known that I, PHILIP PIsToR, a citizen of the United States, and a resident of the city and county of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Corliss Valve-Gears, of which the following is a specification.

My invention relates to improvements in my invention is to furnish a device by means of which the regulation of the steam admission may be automatically controlled from the beginning of the stroke up to the point of cut-off, due to the position of the actuatingeccentric, and to do this, if desired, with but one eccentric, which may also actuate the exhaust-valves.

In Corliss valve-gear as ordinarily c011- structed the steam-admission-valve spindle is firmly keyed to a lever, which is intermittently actuated by a latch. to uncover the valve-opening. This lever receives motion from the wrist-plate and is unhooked by a cam, whose position is regulated by the gov-- ernor, thus allowing said lever to be moved by the dash-pot or weights for closing the valve-opening.

My invention for controlling the cut-off COD. sists of two independent mechanisms controlled by the engine-governor, and one of which regulates the cut-off from, say, seven: eighths steam following to one-half of the sa1ne-that is, seven-sixteenths steam following-and the other from this point down to zero cut-off.

In the accompanying drawings, forming part of this specification, and in which similar letters of reference indicate similar parts throughout the several views, Figure 1 is a side elevation of a radial Corliss valve-gear with my invention for regulating the cut-off attached; Fig. 2, a top view of Fig. 1; Figs. 3 and 4, side elevations of my notched cams which are carried by a sleeve'turned on the steam-admission bracket, the levers attached to these cams, and the pawls carried upon the end of and which effect the tripping of the latch, the pawls being shown raised in Fig. 3 and lowered in Fig. at; and Fig. 5, a skeleton general arrangement showing the connecating levers, the wrist-plate, disc.

Serial No. 494,700. (No model.)

A is a bracket, which is attached to the admission-valve chamber and through which the valve-stem B, controlling the movements of the valve, passes. Upon the bracket A is the loose lever C, which is connected with the wristplate D, Fig. 5, by a rod E, and which receives a positive motion from said wristplate.

F is a lever keyed to the valve-stem B, and which carries a pin G for a dash-pot connection I-I, Fig. 5.

1 (shown in dotted lines in Fig. l) is a block securely fastened to lever F.

J is a latch pivoted on pin K to lever C. This latch can hook over block I by means of notch M on its lower part, and its upper end carries a pin L, upon which are loosely pivoted the pawls a and Z).

70 is a stop carried by lever C to prevent excessive forward movement of latch J.

N O are notched cams carried on bracket A. 0 cl are the notches on these cams with which the pawls a b are adapted to engage, the pawl or engaging the notch c, the pawl b the notch d, as hereinafter described. Fast to the cam N is a lever P and fast to the cam O is a lever B. (See Fig. 2.)

Fig. 5 shows the method of actuating the levers P and R and through them the cams N O by means of the governor.

e is a rod, one end of which is attached to lever P and the other to a lever f, which is pivoted at g.

h is a rod attached to lever B- and to lever f at a point upon the opposite side of its center from that at which the rod e is attached.

1' is a rod connected to lever f and t0 the g0vernor-lever j. Similar rods connect the lever f with the other steam-admission-valve levers, as shown in Fig. 5.

As the speed of the engine increases, the governor-balls rise and by means of the rods and levers shown cause the levers P R and the cams attached to them to move in opposite directions.

The latch J, which is pivoted to the loose lever c and which moves With the same, will during the forward movement of this lever pass over cam N and partly over cam O and on its return motion pawl at will engage notch c of cam N. The motion of the point of pawl a being arrested by the notch c, it will pivot around the pin L, by which it is attached to the latch, thus raising the upper end of this latch and causing the notch M to disengage from block I. (See Fig. 1.) When this is done, the fast lever F will be partially revolved by the dash-pot and the steam-admission valve closed. \Vhen cam N is in this position, the steam is following as far as the eccentric will allow. The lever C and the latch continue their return motion as far as lap may require, allowing pawl a to pass over the notch 0, Figs. 3 and 4, completely and be brought back to its normal position by a spring Z. As the cutoff shortens, cam N is moved in the forward direction of the latch movement, the tripping of the latch connection to lever F being effected earlier and earlier on the return stroke of lever C and latch J. At the extreme forward motion of the latch the notch d in cam O, which has gradually approached notch c in cam N, will be engaged by pawl Z2, which will raise the latch in a manner similar to that described for pawl a. As the cut-off further shortens, cams N and 0 continue their opposite movement, the cut-01f being effected by notch 01 in cam O and is no longer influenced by notch c in cam N, as it is beyond the stroke of the latch. This mo tion of the cam will continue for a lessening of the steam admission until notch (1 comes 011 the line that notch coriginally occupied. lVe have then reached zero cut-oif. Pawl b is provided with a spring similar to that on pawl a for bringing it back to its position.

It will be noticed that in order to allow pawl a to engage notch 0 when the latch occupies its extreme forward position said pawl a must have been drawn over the notch 0, so as to trip the latch J immediately on the return stroke of the latch. I therefore give cam. N the necessary lesser amount of angular vibration to effect this purpose. It follows, therefore, that lever P, which revolves cam N, will have a smaller total angular vibration than lever B, which revolves cam O, the latter cam needing an angular travel equal to that of the latch when within operating range of pawl Z). At seven-sixteenths cut-off pawl 1) partially lifts latch J without detaching same from block in fast arm, enabling pawl a to slide over and into position in its notch c in cam a, so as to fully trip latch J immediately on beginning of return stroke of said latch.

Instead of having cams with different degrees of angular vibration it will be understood that the same effect may be produced by having pawls of different lengths. It might also be advisable under certain conditions to pivot the pawls on separate pins.

The pawl-springs H are so regulated as to cause the pawls to bear on the surface of the cams with a slight pressure, thus forcing them down into the notches just before engaging.

Having thus described my invention, I claim- 1. The herein described device for tripping the latch through which the valve stem and valve of a Corliss engine are operated, consisting of two notched cams adapted to be moved in opposite directions by the rising or falling of the governor balls, and two pawls carried by said latch and adapted to be engaged by the notches on said cams, the whole arranged and operating substantially as set forth.

2. In a Corliss valve gear, in combination, a valve, a valve stem, a lever fast to said valve stem, an eccentric, a pin receiving a positive motion from said eccentric, a latch pivoted to said pin and adapted to engage a stop on said fast lever, said stop, two pawls carried by said latch, two notched cams, a lever adapted to be rocked by the rising or falling of the governor balls, said governor, an arm connecting said lever and governor, an arm attached to one side of the fulcrum of said lever and to one of said notched cams, an arm attached to said lever at the other side of its fulcrum and to the other notched cam, all substantially as and for the purposes set forth.

3. In a Corliss valve gear, in combination, a valve, a valve stem, a lever fast to said valve stem and provided with a stop, an eccentric, a pin receiving a positive motion from said eccentric, a latch pivoted to said pin and adapted to engage a stop on said fast lever, two pawls carried by said latch, two notched cams one of which with its pawl determines the cut off of the valve during its motion in one direction, the other with its pawl determining the cut off of the valve when moving in the reverse direction, a governor, and mechanism operated by the movements of the balls of said governor adapted to give each of said two cams an angular vibration equal approximately to double that which it receives while within range of engagement of its pawl.

PHILIP PISTOR. 

